The present invention relates to a nozzle clogging-preventive device which prevents air from entering the nozzle part and prevents the ink in said nozzle part from drying/solidifying when an ink jet printer is transported, when the power to the printer is turned off, or when the printer is stopped to perform no printing for a ling time while said power remains turned on.
In an ink jet printer, when no printing is performed, the nozzle of an ink jet part is left in the atmosphere while the nozzle is filled with an ink, causing the ink to dry and solidify and leading to nozzle clogging. Also, when an ink jet printer is transported or stored, air enters the nozzle and the ink in the nozzle dries and solidifies to cause nozzle clogging as does for non-printing condition.
In order to cope with the problem encountered when no printing is performed, that is, when the power is turned off or when the printer is stopped for a long time while the power is turned on, a cap member (the first cap adhering device) has conventionally been provided which adheres to the nozzle surface to prevent ink drying. In addition to the cap adhering device mentioned above, in order to cope with the problem encountered when the printer is transported or stored for a long time, the second cap adhering device has also been provided which prevents air from entering the nozzle and prevents the ink from drying while said cap is filled with a maintenance liquid.
Accordingly, in a conventional printing equipment, said two different cap adhering devices as a nozzle clogging-preventive means have been required, making the equipment componentally complex.
The second cap adhering device used for said transportation and long-period storage has required a complex operation to have the cap filled with the maintenance liquid. Also, the handling of said device has been very troublesome.
On the other hand, when air had entered to nozzle due to some cause to develop nozzle clogging, a nozzle recovery operation has been performed such that, while said cap has been allowed to adhere to the nozzle surface utilizing said second cap adhering device, a sucking means such as an injector has been connected to said cap to lead the internal pressure of the cap and nozzle part to a negative value by said sucking means, allowing the bubbles entering the nozzle to be extracted from the nozzle.
Thus, conventional ink jet printers have had such problems as the complex composition of the first and second cap adhering devices mentioned above, the troublesome operation of the maintenance liquid filling relating to said second cap adhering device, and the complex nozzle recovery operation when bubbles enter the nozzle, in order to prevent nozzle clogging.
In a system in which a single cap member is used, e.g., that of Iwagami et al., U.S. Pat. No., 4,734,768, issued on Mar. 29, 1988, the mechanisms for causing the cap to cover the nozzle, for controlling ink flow to the nozzle, and for controlling the maintenance liquid flow to the cap, are controlled so that ink is prevented from flowing to the nozzle when power is on but printing is not being performed and so that maintenance liquid flow is provided when printing power is off for a long time period. However, no provision is provided to control ink flow when printing power is shut off for only a relatively short time period.